Quenching across quantum critical points: Role of topological patterns

Diptiman Sen, Smitha Vishveshwara

Research output: Contribution to journalArticle

Abstract

We introduce a one-dimensional version of the Kitaev model consisting of spins on a two-legged ladder and characterized by Z2 invariants on the plaquettes of the ladder. We map the model to a fermionic system and identify the topological sectors associated with different Z2 patterns in terms of fermion occupation numbers. Within these different sectors, we investigate the effect of a linear quench across a quantum critical point. We study the dominant behavior of the system by employing a Landau-Zener-type analysis of the effective Hamiltonian in the lowenergy subspace for which the effective quenching can sometimes be non-linear. We show that the quenching leads to a residual energy which scales as a power of the quenching rate, and that the power depends on the topological sectors and their symmetry properties in a non-trivial way. This behavior is consistent with the general theory of quantum quenching, but with the correlation length exponent ? being different in different sectors.

Original languageEnglish (US)
Article number66009
JournalEPL
Volume91
Issue number6
DOIs
StatePublished - Sep 1 2010

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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